Platelet Storage Pool Deficiencies

What are platelet storage pool deficiencies?

Platelet storage pool deficiencies are bleeding disorders caused by problems with platelet granules.  

Granules are little sacs inside the platelet where proteins and other chemicals are stored. 

Platelets are used by our bodies to create something like an internal bandage to stop bleeding. This is called a platelet plug. During the process of making a platelet plug, the platelets change shape.  

Chemicals inside the granules are pushed out into the bloodstream. These chemicals signal other platelets to come and help. The chemicals allow the platelets to stick together. They also stick to the blood vessel to repair it and hold the platelet plug in place.  

If this does not happen, a good platelet plug cannot form. The body could bleed too much.  

The chemicals inside the granules also cause injured blood vessels to constrict (tighten) to help stop bleeding.

There are two types of granules: 

• Dense granules 
• Alpha granules 

The most common deficiencies are caused when platelets fail to empty the contents of the granules into the bloodstream. But some storage pool deficiencies are caused by a lack of granules. 

• Delta storage pool deficiency is caused by a lack of dense granules and the chemicals normally stored inside them. Without these chemicals, platelets are not activated properly. Injured blood vessels do not constrict to help stop bleeding. This type of bleeding problem can be part of other inherited conditions including Hermansky-Pudlak syndrome and Chediak-Higashi syndrome. 
• Gray platelet syndrome is a very rare platelet function disorder caused by a lack of alpha granules and the chemicals normally stored inside them. It is called gray platelet syndrome because the platelets appear gray under a microscope. Without these chemicals, platelets cannot stick to the blood vessel wall, clump together the way they should, or repair the injured blood vessel. 

Symptoms of platelet storage pool deficiencies 

Symptoms of storage pool deficiencies vary from one person to the next. But they are usually mild to moderate. 

People with storage pool deficiencies may have the following: 

• Easy bruising 
• Nose bleeds 
• Bleeding from gums 
• Heavy or prolonged menstrual bleeding or bleeding after childbirth 
• Abnormal bleeding after surgery, circumcision, or dental work

Platelet storage pool deficiencies diagnosis

The diagnosis of storage pool deficiencies requires a careful medical history. It also requires a series of tests. 

In people with storage pool deficiencies: 

• Platelets do not clump together the way they should in special laboratory tests 
• Granules may not be visible when platelets are looked at with an electron microscope 

Platelet storage pool deficiencies treatment

Most people with storage pool deficiencies only need treatment during surgical procedures (including dental work) and after an injury.

Platelet storage pool deficiencies may be treated with the following: 

• Antifibrinolytic medicines, which are used to help stop bleeding 
• Desmopressin, which can help increase clotting factor but may not be useful in alpha granule deficiency 
• Platelet transfusions 

People with inherited platelet disorders should not take: 

• Aspirin 
• Nonsteroidal anti-inflammatory drugs (such as ibuprofen and naproxen) 
• Blood thinners  

These drugs can make bleeding symptoms worse.